A head on crash on Highway 97 just south of La Pine seriously injured four people and closed the highway for several hours Monday morning. Police say a Ford pickup pulling an empty horse trailer was southbound on Highway 97 just after 9 a.m. Monday morning when it jackknifed into the northbound lane. A northbound SUV struck the Ford pickup' s driver's side. The pickup driver and one of her passengers was airlifted to St. Charles Medical Center in Bend. Two other passengers were taken to the hospital by ambulance. Names are not being released at this time.